How to keep (and rotate secrets)

Managing our numerous secrets can be quite a chore, requiring manual key rotation and updating. This may get more complex in the future, especially if we move to each feedstock having independent keys scoped to only it's packages. It would be good to figure out a way to manage this, since it will reduce key person risk (since the task will be easier and more welcoming to less knowledgeable users) and other operational risks more broadly.

One potential solution for this is the [hashicorp vault](https://www.vaultproject.io/) and [cloud vault](https://www.hashicorp.com/cloud-platform) products.

This issue is aimed at discussing the problem, potential solutions, and implementation plans.